Building slab



Patented May 4, 1926.

UNITED STATES PATENT OFFICE.

LEROY BAUMGARTL, OF HUBBARD WOODS, ILLINOIS, ASSIGNOR T0 FEDERAL CEMENT TILE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

BUILDING SLAB.

Application led January 12, 1925. Serial No. 1,741.

To all whom t may concern/j Be it known that I, LnRor BAUMGARTL, a citizen of the United States, residing at Hubbard Woods, 1180 Oakley Avenue, in the county of Oook and State of Illinois, have invented new and useful Improvements in Building Slabs, of which the following is a full, clear, concise, and exact description,reference being had to the accompanying drawing, forminga part of this specication. l

This invention relates to improvements in building slabs or tiles of concrete, clay or likesubstances which are used in the construction of walls, floors, ceilings, roofs, etc., and more particularly to a tile or slab of this character composed of concrete and some aggregate having spongycharacteristics, whereby theinished tile or slab is adapted to readily receive and positively hold .nailsdriven into said slabV andwliereby the heat insulatingv qualities of the'slab are greatly increased. l Y' f In the use of concrete slabs or tiles in the construction of roofs it frequently is desirable to cover said: tile with shingles or other coatingswhich can only beproperly secured to the tiles by nailing the shingles or covering thereon. The practice in the construction of roofs of this kind has been to construct the concrete roof on the job and then pour on the completed concrete roof the desired spongyA aggregate to provide the desired nailing surface.l This method of construction has very serious installation and maintenance disadvantages and results in a wasteaof material, all of which are obviated in constructingsuch tiles according` to the teachings of this invention. l One of the objects of this invention resides, therefore, in constructing a composite tile of concrete and composite aggregate which is adapted to receive and firmly hold nails andthe like and whereby a'roof of the character Ydescribed can ,be constructed with- -the use of less concrete, whereby marked economies areeffected in the handling of the parts in shipping and installation, whereby a more uniform construction throughout the entire surface vof the roof is procuredbecause of the adaptability for the requiredregulation in the tile construction by standardized factory methods and whereby the heat insulating quality of the finished slab is much greater than in slabs constructed solely of concrete.

As illustrated in the drawings, the tileis constructed of a concrete base 4, which is preferably equipped with a steel reenforcement 5 ofeither steel rods or steel netting. To the upper surface of this concrete base is secured the composite aggregate 6 which is utilized as the nailing surface,and'which also serves tovmaterially increase theheat insulating `quality ofthe completed tile. In the construction of this character oftile a formfor mold of the desired dimensions is used, into which the ingredients used. in the layers ofthe composite tile are poured.

The tile may be made by any `one. of a number of methods, but in the preferred method the compositeaggregate 46 i slirst poured, or poured and tamped, into the mold. Onto vvthis layer of.l composite aggregate, preferably while itsv upper surface is still soft, is poured, or poured and tamped, the layer 7 of concrete, whichconstitutes the concrete between the layer of the composite aggregate and thesteel reenforcementy, i y,

AWhen this layer 7 of concrete has been poured into the mold the steel reenforcement 5 is placed in position, after which the layer 8, which constitutes the lower portion of the concrete layer 4C, is poured, or vpoured and tamped, on top of the steel reenforcement; By pouring, or pouring and tamping, thel concrete on the surface of the composite aggregate 6, while it is still ina soft or tacky condition, a better bond is obtained between the spongy aggregate and -the concrete.

than would be the case if the surfacel of the composite aggregate was permitted to harden before the concrete is pouredA into the mold. However, suitabletiles or slabs can be yconstructed by pouringthe concrete in the mold after the spongy aggregate 6 has hardened, but `the preferred form is to pour this conc-rete on the soft or tacky surface of the composite aggregate 6.

The method above described is'the preferred method for making tiles of this character, because the surface 9 of the concrete layer l of the slab is exposed at the upper face of the mold, and, consequently, it is possible to smoothen this upper surface in any of the well known methods in the prior art and thereby get a concrete surface on the slabs of the desired smoothness. Inasinuch as the tiles in the ultimate building construction are positioned on the roof with the concrete face of the tile on the interior of the building, it is obviousy more desirable to have the smoothest surface on the concrete face of the tile. The surface of the composite aggregate 6 being on the exterior of the roof does not require a smooth surface, and, furthermore, it is usually covered with shingles or some other roof coating which would obscure any irregularities or roughness in its surface.

Except for the fact that is has been found that it is considerably easier to obtain a smooth concrete face on these tiles by constructing the tile as above described, there is no real preference in the method described over the method of constructing these tiles, in which the concrete base ,4, with its reenforcement 5, is first poured, or poured and tamped, into the mold and while the upper surface of this concrete layer is still soft pouring or pouring and tamping the composite aggregate layer 6V thereon. Either one of these methods, or any slight modiiication thereof, in which a tile having a concrete base and a composite aggregate bonded thereto in substantially the proportions to be hereinafter described can be utilized, depending upon the manufacturing and installation conditions and requirements.

The manufacture of these slabsin the factory in forms or moldsresults in a uniform product and in a slab having a strength capable of resisting without breakage the necessary handling in shipping and installation. Thus, it has beenfound in practice that composite tiles of this character can be manufactured to vresist the ordinary usage in handling and installation without breakage in which the concrete base is substantial- 1y one (l) inch thick and in which the i spongy aggregate secured to said base is one and one-half (l1/2) inches thick, making an over-all thickness for the completed tile of two and one-half (2l/2) inches. A concrete tile one (l) inch in thickness is too fragile toV withstand the usual effects of handling and installation but when this one (l) inch concrete slab is fitted with the one and one-half (l1/ 2)A inch coating of spongy aggregate, the strength of the completed tile is sufliciently great so that breakage in handling and installation is not excessive. This layer of spongy aggregate also materially increases the heat insulating quality of the completed tile.

For this reason, when these tiles are constructed according to standardized factory methods in forms or molds provided therefor, the amount of concrete required kin constructing a roof 'on which it is desired to place a coating of spongy aggregate for nailing purposes can be very materially decreased. Likewise, it is exceedingly difficult to commercially construct a roof which has a marked pitch or inclination with a coating of this spongy aggregate, except with the composite tile manufactured in accordance with the teachings of this invention.

In constructing a roof with such tiles they are placed side-by-side and are cemented togethei at their abutting edges by an elastic cement-filler. The composite aggregateV 6 which is placed on the top of the concrete base t is preferably made of mineralized sawdust mixed with Portland cement and water. This composite aggregate hasheat insulating qualities whichv are greatly superior to those of ordinary concrete and the composite tile can be used to advantage because of its increased heat insulating property, even when it is not desired to utilize the nail-retaining characteristics to the aggregate 6. Obviously, any other composite aggregate in which nails can be easily driven and which will firmly hold the nails in position, and which has the required heat insulating properties, can be substituted for the specific form just described. Y

The tiles constructed in accordance with the teachings of this invention should be made of such a size that they can be readily handled in shipment and during installation and a convenient size has been one in which the tile isfive (5) feet long by two (2) feet wide by two and one-half (2l/2) inches thick. rIfhe size of the tile can obviously be designed to suit special requirements, but should not be made too large so as to make the handling thereof unnecessarily diiiicult.

From the foregoing description, it will now be evident that by manufacturing a composite tile of the character described in the factory where the construction is independent of weather conditions and can be positively regulated, it is possible to obtain a composite tile in which the concrete necessary to give it the desired strength can be materially reduced, and in which a completed tile o-f uniform construction is obtained, which reduces the necessary cost of handling and installation incident to the -construction of roofs in which the spongy aggregate is poured upon the concrete roof after the concrete roof has been Vcompletely installed. Moreover, the tile serves the dual function of providing the nailing surface and of increasing the heat insulating quality of the completed slab. n

Obviously, this invention is not limited to the specific embodiment thereof herein illustrated and described, but is capable of other applications and variations, the scope of the invention being set forthcin the following claims: p Y

Having thus described/my invention, what I claim is new and desire to secure by Letters Patent of the United States is:

1. A roofing tile or slab as an article of manufacture, comprising a layer of concrete and a layer of composite material adapted to receive and hold nails molded together in bonded relationship, each of said layers being of insulicient strength to alone sustain the slab and roof load when the slab is supported at its ends, the united strength of the combined bonded layers being sufcient to sustain the slab and roof load when the slab is supported atits ends and whereby a material saving in concrete is effected.

2. A roofing tile or slab as an article of manufacture, comprising a layer of concrete of prescribed dimensions to facilitate handling, shipping and installation, and of a thickness insuflicient to properly sustain the roof load when the slab is supported at its ends and a layer of composite. aggregate adapted to receive and firmly hold nails secured in bonded relation to said layer of concrete, the two bonded layers cooperating in said bonded relation to adequately sustain said slaband the roof lo-ad when the slab is supported at its ends whereby a material saving in concrete is effected.

In witness whereof, I have hereunto subscribed my name.

LEROY BAUMGARTL. 

